1. Field of the Invention
This invention relates generally to telescopic and other optical sighting systems for use on guns or related items, and more particularly to an optical sighting system that includes an improved reticle for sniper rifles, hunting rifles, and the like.
2. Description of Related Art
A reticle is a grid or pattern placed in either of two focal planes of an optical instrument, such as a rifle scope, to establish scale or position. Various gun sights known in the art include reticles having an optical center, a vertical line, a horizontal line that intersects the vertical line at the optical center, and various forms of markings at predetermined distances along the vertical and horizontal lines for forming measuring points.
The mil-dot (or milliradian-dot) reticle uses precisely sized and shaped dots, sometimes separated by dashes midway between the dots, for enabling a user to quickly and effectively determine the approximate distance from the optic to a target, and to adjust his or her aim when aiming at distant targets. A mil-dot reticle enables a user to adjust the trajectory of a shot to compensate for bullet drop (caused by gravity), and for bullet drift (caused by wind).
One example of a mil-dot reticle is shown in Thomas et al., U.S. Pat. No. 6,729,062, which teaches a reticle that incorporates an optical center and a plurality of measuring points. The measuring points are formed by a primary vertical line, a primary horizontal line intersecting the primary vertical line at the optical center, a plurality of dots intersecting the primary lines and evenly spaced at a predetermined distance along the primary lines, a plurality of secondary lines intersecting one of the primary lines and evenly spaced between the dots therein. The secondary lines are shorter than 0.2 mil. Alternatively, the reticle further incorporates at least one post on at least one end of the primary lines with post hash marks thereon.
While the Thomas reference teaches a reticle with a plurality of dots, or hollow circles, that form measuring points, these circles can be difficult to use with great accuracy due to their curved shape. The Thomas reticle only includes two effective measuring points, the points at which the circle intersects the vertical line (or the horizontal line).
Another similar or related references includes Sammut, U.S. Pat. No. 6,681,512, which teaches a reticle having a ring which includes a plurality of crosshairs that enable a gun to be adjusted for various factors, including distance and wind.
Other similar or related references include U.S. application number 2005/0005495, U.S. Pat. No. 6,591,537, and U.S. application number 2002/0139030.
The above-described references are hereby incorporated by reference in full.
The prior art teaches various forms of reticle having a dots and/or hollow circles incorporated into the reticle. However, the prior art does not teach a reticle that includes a plurality of quadrilaterals for providing at least four measuring points. The four measuring points of the quadrilateral easier to use provide two measuring points that are vertically spaced a first distance, and two measuring points that are horizontally spaced a second distance. The first distance (vertical spacing) may or may not be the same as the second distance (the horizontal spacing), unlike a circle which is symmetrical and can have only one distance between the two aiming points. The present invention fulfills these needs and provides further related advantages as described in the following summary.